ARM: dts: msm: Add USB OTG VBUS regulator for APQ8084 MTP

Add a regulator to control the 5V boost OTG functionality of
the SMB349 charger, and a corresponding phandle reference to
the USB device to enable it in host mode.

Change-Id: Idc6f8aa856cef82f62c8280d7b787157bf64ab3f
CRs-Fixed: 561751
Signed-off-by: Jack Pham <jackp@codeaurora.org>